Understanding Peptides: From Research to Real Life
- annewells5
- Jul 31
- 9 min read
Updated: Aug 2
Part 1: What Are Peptides, and Why Are GLP-1 Medications Changing Medicine?
Published August 2026 • By Anne Wells, ND
Ready to learn more?
The word peptide is suddenly everywhere.
It comes up in conversations about diabetes, weight management, muscle recovery, sleep apnea, hormone health, PMOS(formerly known as PCOS), healthy aging, and even brain function. Some peptides are established medications supported by decades of research. Others are still experimental, with far less evidence than their popularity might suggest.
This is the first article in a new educational series designed to separate solid research from social-media hype.
My goal is not to suggest that every peptide is beneficial, or that everyone needs one. It is to explain what peptides are, why they have become such an important area of medicine, and how to distinguish well-studied treatments from therapies that remain investigational.
We will begin with the most familiar and extensively researched group: GLP-1–based medications.
What Is a Peptide?
Peptides are short chains of amino acids, the same building blocks that make up proteins.
The body naturally produces hundreds of peptides that act as signaling molecules. They carry messages between cells and help regulate processes such as:
Appetite and digestion
Blood sugar and insulin release
Growth and metabolism
Immune activity and inflammation
Reproduction and hormone signaling
Blood pressure and fluid balance
Tissue repair and wound healing
Insulin is one familiar example of a peptide hormone. Other naturally occurring peptides include glucagon, oxytocin, vasopressin, and glucagon-like peptide-1, better known as GLP-1.
Researchers can study these natural signaling molecules and develop medications that mimic, strengthen, or modify their effects. Advances in peptide design have made it possible to create therapies that last longer in the body, bind more selectively to their targets, and are easier to administer than earlier peptide medicines (Xiao et al., 2025; Zheng et al., 2025).
How Are Peptides Different From Proteins?
Peptides and proteins are both made from amino acids. The main difference is generally their size and complexity.
Peptides are usually shorter and structurally simpler. Proteins are generally longer, fold into more complicated three-dimensional shapes, and may carry out larger structural, transport, or enzymatic functions.
There is no single universally accepted cutoff where a peptide becomes a protein, so the distinction is not always exact. A simple way to think about it is:
Peptides often act as targeted biological messages, while proteins tend to perform larger or more complex biological jobs.
Peptides can bind very specifically to certain receptors, which makes them useful as medications. Their weakness is that digestive enzymes may break them down quickly. That is why many peptide medications are given by injection, although oral peptide delivery continues to improve.
Why Are GLP-1 Medications Considered Peptides?
Wondering if GLP-1 therapy might be appropriate for you?
GLP-1 is a peptide hormone naturally released from the intestine after eating.
It helps coordinate the body’s response to food by:
Increasing insulin release when blood glucose is elevated
Reducing inappropriate glucagon release
Slowing stomach emptying
Sending fullness signals to the brain
Helping regulate appetite and food intake
Natural GLP-1 is broken down within minutes. Researchers therefore developed modified peptide molecules that activate the same biological pathways but remain active much longer.
Semaglutide, found in medications such as Ozempic®, Wegovy®, and Rybelsus®, is a modified GLP-1 analog.
Tirzepatide, found in Mounjaro® and Zepbound®, is an engineered peptide that activates both the GLP-1 receptor and the glucose-dependent insulinotropic polypeptide, or GIP, receptor. It is therefore more accurately described as a dual GIP/GLP-1 receptor agonist.
Although these medications are often grouped together as “GLP-1s,” they are not identical. Their structures, receptor targets, approved indications, and clinical effects differ.
Why Are GLP-1 Medications Changing Medicine?
GLP-1 medications were first developed for type 2 diabetes, but their effects extend well beyond blood sugar control.
In the STEP 1 trial, adults with overweight or obesity who received weekly semaglutide plus lifestyle support lost an average of approximately 14.9% of their initial body weight over 68 weeks, compared with about 2.4% in the placebo group (Wilding et al., 2021).
In the SURMOUNT-1 trial, adults with obesity who received tirzepatide experienced substantial and sustained weight reduction over 72 weeks, with average losses approaching 21% at the highest studied dose (Jastreboff et al., 2022).
A direct comparison published in 2025 found that tirzepatide produced greater average weight loss than semaglutide in adults with obesity who did not have diabetes, although both medications produced clinically meaningful results (Jastreboff et al., 2025).
The significance of these medications is not limited to weight loss. A major 2025 scientific review concluded that GLP-1–based therapies can improve glucose control and body weight while reducing cardiovascular and kidney-related illness in appropriate patients with type 2 diabetes or obesity (Drucker, 2025).
These findings are changing the way medicine understands obesity. Body weight is influenced by far more than discipline or willpower. Genetics, appetite signaling, hormones, sleep, medications, stress, insulin resistance, environment, and brain pathways all contribute.
GLP-1 medications are giving clinicians another way to address those biological drivers.
Beyond Weight Loss: Obstructive Sleep Apnea
One of the strongest examples of benefits beyond weight loss comes from research on
obstructive sleep apnea, or OSA.
OSA causes repeated narrowing or closure of the airway during sleep, leading to drops in oxygen, disrupted sleep, daytime fatigue, and increased cardiovascular risk.
The two phase 3 SURMOUNT-OSA trials studied tirzepatide in adults with obesity and moderate-to-severe OSA. After 52 weeks, treatment reduced the number of breathing interruptions during sleep, body weight, hypoxic burden, inflammation, and systolic blood pressure. Participants also reported improvement in sleep-related symptoms (Malhotra et al., 2024).
Based on these findings, the FDA approved tirzepatide in December 2024 for moderate-to-severe OSA in adults with obesity, alongside a reduced-calorie diet and increased physical activity.
This does not mean tirzepatide automatically replaces CPAP or other airway treatments. OSA care still needs to be individualized. However, it demonstrates how treating obesity as a biological disease may improve related health conditions, not simply change a number on the scale.
GLP-1 Medications and PCOS
Polycystic ovary syndrome, or PCOS, is a complex endocrine and metabolic condition that may involve insulin resistance, irregular menstrual cycles, elevated androgen activity, infertility, and difficulty managing weight.
Because insulin resistance and obesity can worsen PCOS symptoms, researchers have been studying whether GLP-1 receptor agonists may help address some of its metabolic features.
A 2025 systematic review and meta-analysis found that GLP-1 receptor agonists reduced body weight, BMI, and insulin resistance in women with PCOS. Gastrointestinal adverse effects, including nausea and vomiting, were more common, and the authors noted that longer-term research is still needed (Lin et al., 2025).
A 2026 systematic review found modest short-term weight loss in women with PCOS and overweight or obesity but concluded that evidence for reproductive, psychological,
and broader metabolic outcomes remains uncertain because much of the available research is small or low quality (Forslund et al., 2026).
The most accurate way to describe the current evidence is:
GLP-1 medications may help address the weight and insulin-resistance components of PCOS, but they should not yet be presented as a treatment for every aspect of the condition.
More research is needed to clarify their effects on ovulation, menstrual regularity, fertility, androgen-related symptoms, and long-term outcomes.
Pregnancy planning also matters. GLP-1 medications are not used during pregnancy, and people who may become pregnant need individualized counseling about contraception and when to discontinue treatment before attempting conception.
GLP-1 Medications During Perimenopause and Menopause
Many women notice that weight management becomes more difficult during perimenopause and after menopause.
Hormonal changes may affect sleep, appetite, insulin sensitivity, muscle mass, fat distribution, and where weight is stored. At the same time, aging-related muscle loss can reduce energy expenditure and make weight regain more likely.
Large obesity trials have included many middle-aged and older women, and GLP-1–based medications clearly remain effective in these age groups. However, relatively few randomized trials have been designed specifically to study perimenopausal or postmenopausal women.
A 2024 observational study of postmenopausal women taking semaglutide found that those also using menopausal hormone therapy experienced greater average weight loss than women not using hormone therapy. Because the study was observational rather than randomized, it cannot prove that hormone therapy caused the difference (Hurtado et al., 2024).
A newer observational study reported a similar association among postmenopausal women using tirzepatide: concurrent menopausal hormone therapy was associated with greater weight loss and improvement in some cardiometabolic measures. Again, the results are interesting but not yet definitive because women were not randomly assigned to hormone therapy (Castaneda et al., 2026).
GLP-1 medications are not treatments for menopause itself. They may, however, be useful for appropriately selected women who are also experiencing obesity, overweight with related health risks, or metabolic dysfunction.
For women in midlife, treatment should also emphasize:
Adequate protein
Resistance training
Muscle preservation
Bone health
Sleep quality
Hormone-related symptoms
Hydration and digestive tolerance
Sustainable nutrition rather than excessive restriction
This is particularly important because rapid weight loss can include some loss of lean mass as well as body fat. A 2025 review emphasized the need to pay closer attention to muscle health as increasingly effective GLP-1–based medications produce larger and faster reductions in body weight (Drucker, 2025).
Why Are Peptides Suddenly Everywhere?
Peptides are not new. Insulin has been used as a medication for more than a century, and the first GLP-1 receptor agonist was approved in the United States more than 20 years ago.
What has changed is the science.
Researchers can now create peptide medications that:
Resist rapid breakdown
Remain active for days rather than minutes
Bind selectively to one or more receptors
Combine several metabolic signals in one molecule
Produce clinically meaningful outcomes in chronic diseases
The success of semaglutide and tirzepatide has accelerated interest in next-generation therapies targeting GLP-1, GIP, glucagon, amylin, and other pathways. Several newer peptide-based combinations are already in advanced clinical development (Drucker, 2025).
But increased interest brings an important caution.
Not All Peptides Have the Same Evidence
The term peptide therapy covers a very broad range of substances.
Some peptide therapies:
Are FDA-approved medications
Have been studied in thousands of human participants
Have established dosing, safety information, and monitoring standards
Have demonstrated improvements in meaningful clinical outcomes
Others:
Have mainly been studied in animals or laboratory models
Have limited human safety information
Remain investigational
Are marketed with claims that exceed the available evidence
A peptide’s popularity does not establish that it is safe or effective.
Every therapy should be evaluated individually by asking:
Has it been studied in humans?
Was the research randomized and controlled?
How many people were included?
Were outcomes clinically meaningful?
Is it FDA-approved for the proposed use?
What is known about manufacturing quality and long-term safety?
This distinction between established evidence and emerging research will be a central theme throughout this series.
From Research to Real Life
GLP-1 medications are not miracle drugs, and they are not appropriate for everyone.
They can cause gastrointestinal side effects, require careful dose escalation, and may be inappropriate for people with certain medical histories. They also work best as part of a broader plan that supports nutrition, hydration, movement, sleep, bowel function, and preservation of muscle.
At the same time, they are a powerful example of what can happen when researchers learn from the body’s own signaling systems.
Peptide medicine is developing quickly. My goal in this series is to slow the conversation down enough to ask the questions that matter:
What does the research actually show? How strong is the evidence? What remains uncertain? And what might these findings mean in real life?
Next time, we’ll explore how GLP-1 medications actually work inside the body.
Ready to Learn More?
If you're wondering whether GLP-1 medications, hormone therapy, or other evidence-based approaches may be appropriate for you, I'd be happy to help. I provide telemedicine appointments for patients throughout Washington State, including Seattle, Spokane, Bellingham, Vancouver, the San Juan Islands, Whidbey Island, the Olympic Peninsula, and Eastern Washington.
About the Author
Dr. Anne Wells is a licensed naturopathic physician and founder of Adaptive Wellness, where she provides evidence-based, personalized care through telemedicine for patients throughout Washington State. She has a special interest in perimenopause and menopause, hormone optimization, metabolic health, GLP-1 medications, digestive health, thyroid disorders, and healthy aging. Her goal is to help patients uncover the root causes of their symptoms and create practical, sustainable treatment plans that fit their lives.
When I'm not seeing patients, you'll often find me exploring the Pacific Northwest, currently by sailboat, where I'm continually reminded of how movement, nature, and time outdoors contribute to overall health and well-being.
Interested in the science? The references below include many of the landmark studies and recent reviews discussed in this article for those who would like to explore the research in more depth.
Research References
Castaneda R, et al. The role of menopause hormone therapy in modulating weight loss with tirzepatide in postmenopausal women. The Lancet Regional Health – Americas. 2026.
Drucker DJ. GLP-1-based therapies for diabetes, obesity and beyond. Nature Reviews Drug Discovery. 2025.
Forslund M, et al. GLP-1 receptor agonist treatment in women with polycystic ovary syndrome: a systematic review and meta-analysis. European Journal of Endocrinology. 2026.
Hurtado MD, et al. Weight loss response to semaglutide in postmenopausal women with and without menopausal hormone therapy use. Menopause. 2024.
Jastreboff AM, et al. Tirzepatide once weekly for the treatment of obesity. New England Journal of Medicine. 2022;387:205–216. DOI: 10.1056/NEJMoa2206038.
Jastreboff AM, et al. Tirzepatide as compared with semaglutide for the treatment of obesity. New England Journal of Medicine. 2025.
Lin S, et al. Efficacy and safety of GLP-1 receptor agonists on weight management and metabolic parameters in women with PCOS: a systematic review and meta-analysis. Scientific Reports. 2025.
Malhotra A, et al. Tirzepatide for the treatment of obstructive sleep apnea and obesity. New England Journal of Medicine. 2024. DOI: 10.1056/NEJMoa2404881.
Wilding JPH, et al. Once-weekly semaglutide in adults with overweight or obesity. New England Journal of Medicine. 2021;384:989–1002. DOI: 10.1056/NEJMoa2032183.
Xiao W, et al. Advance in peptide-based drug development: delivery platforms, therapeutics and vaccines. Signal Transduction and Targeted Therapy. 2025.
Zheng B, et al. Therapeutic peptides: recent advances in discovery, synthesis and clinical applications. 2025.
This article is intended for educational purposes only and is not a substitute for individualized medical advice, diagnosis, or treatment.
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